Abstract
The effect of heat treatment on the sulfide stress cracking (SSC) resistance of CA-6NM, CA-15, and AISI 410 stainless steels were evaluated using uniaxially stressed tensile specimens and notched C-ring specimens. The embrittling environment was an aqueous solution containing 5% NaCl, 0.5% acetic acid saturated with H2S at room temperature. It was observed that the susceptibility of these alloys to SSC was dependent on yield strength and microstructure, which could be controlled by heat treatment. Specifically, the SSC resistance of CA-6NM was significantly improved after a double tempering treatment of 677 C followed by 607 C as compared to a CA-6NM alloy which was only single tempered at 607 C. At equivalent yield strength levels, CA-6NM was less susceptible to SSC than CA-15 or 410, although it was not immune. The effect of heat treatment on the SSC embrittlement phenomenon in these alloys was rationalized on the basis of microstructural changes occurring during tempering.
